The correct answer is D. No, because of savings in site labour.
Prefabricated components are made in a factory under controlled conditions, which can lead to higher quality and less waste than traditional cast-in-situ construction. Additionally, prefabricated components can be assembled quickly and easily, which can save time and money on site. As a result, prefabricated components can often be more cost-effective than traditional cast-in-situ construction, even when the initial cost of the components is higher.
Option A is incorrect because the overheads and handling costs associated with prefabricated components are often offset by the savings in site labour.
Option B is incorrect because the high order of quality control for prefabricated components can actually lead to lower costs in the long run, as it can help to prevent defects and costly repairs.
Option C is incorrect because the repetitive manufacture of a number of elements does not necessarily lead to lower costs, as the cost of the components must be balanced against the cost of transportation and assembly.